http://aphnetworks.com/reviews/logitech_mx5500_revolution

I’ve had my MX3200 for a year and five months now, and it has been alright, but the last few months I’ve experienced times of frustration:
Sometimes when I write a character (which requires the shift-button??), the character is being repeated until I hit another key, even though I released the first key. The problem is not related to the key itself, so I guess it’s a problem regarding weak wireless reception or something. When the problem first occurs, it can happen over and over again for hours, while other times there can be days/weeks when there’s no problem at all. This makes me suspect that maybe the signal/noise ratio is too low; maybe the signal reception is too weak on this model and that the problem occurs when the noise from cellulars etc is having its peaks?

What made me suspect the reception quality in the first place, was when I first plugged the receiver in the back of my computer, curious to try out my new keyboard. The reception was less than low: Not all keystrokes were recorded, and I had to use the equipped USB extension cable to place the receiver nearer my keyboard. Considering that the back of my computer is no more than 1,5 m away from the keyboard — though visually hidden by the cabinet itself — I think that’s poor reception.

Anyways, I haven’t had this problem with any other (Logitech) wireless keyboards I’ve had, so I hope and think it’s just this model. Therefore, I found the review linked to above interesting, especially since they mention good reception on the MX5500.